U.S. patent application number 16/181832 was filed with the patent office on 2020-05-07 for cable hose with conductive electromagnetic interference shield.
The applicant listed for this patent is The ESAB Group Inc.. Invention is credited to Michael NADLER, Andrew RAYMOND, James TANTILLO.
Application Number | 20200143958 16/181832 |
Document ID | / |
Family ID | 67874400 |
Filed Date | 2020-05-07 |
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United States Patent
Application |
20200143958 |
Kind Code |
A1 |
TANTILLO; James ; et
al. |
May 7, 2020 |
CABLE HOSE WITH CONDUCTIVE ELECTROMAGNETIC INTERFERENCE SHIELD
Abstract
A cable hose suitable for welding or cutting systems includes
tubing, one or more conductors, and an annular electromagnetic
interference (EMI) shield. The EMI shield is disposed radially
interiorly of at least a portion of the tubing and radially
exteriorly of the one or more conductors. Thus, the EMI shield: (1)
prevents EMI emanating from the one or more conductors from exiting
the cable hose radially; and (2) conducts current between
components of a welding or cutting system.
Inventors: |
TANTILLO; James; (Enfield,
NH) ; NADLER; Michael; (Wilmot, NH) ; RAYMOND;
Andrew; (Lebanon, NH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
The ESAB Group Inc. |
Florence |
SC |
US |
|
|
Family ID: |
67874400 |
Appl. No.: |
16/181832 |
Filed: |
November 6, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01B 13/0013 20130101;
H01B 7/425 20130101; H01B 9/029 20130101; B23K 10/00 20130101; H01B
11/1813 20130101; H01B 13/0165 20130101; H01B 13/221 20130101; H01B
9/001 20130101; B23K 9/32 20130101; H01B 7/0072 20130101 |
International
Class: |
H01B 9/00 20060101
H01B009/00; H01B 9/02 20060101 H01B009/02; B23K 10/00 20060101
B23K010/00 |
Claims
1. A cable hose suitable for welding or cutting systems,
comprising: tubing; one or more conductors; and a conductive,
annular electromagnetic interference (EMI) shield that is disposed
radially interiorly of at least a portion of the tubing and
radially exteriorly of the one or more conductors so that the EMI
shield: (1) prevents EMI emanating from the one or more conductors
from exiting the cable hose radially; and (2) conducts current
between components of a welding or cutting system.
2. The cable hose of claim 1, wherein the EMI shield is embedded
within the tubing.
3. The cable hose of claim 2, wherein the tubing is formed from an
insulator and the EMI shield is embedded within the tubing by
molding the insulator over the EMI shield.
4. The cable hose of claim 2, wherein the one or more conductors
are embedded within the tubing.
5. The cable hose of claim 4, wherein the tubing comprises:
monolithic tubing that is disposed radially exteriorly and radially
interiorly of the EMI shield and that extends around and between
the one or more conductors to define: (1) a discrete passageway for
the EMI shield that provides a closed path from a first end of the
cable hose to a second end of the cable hose for the EMI shield;
(2) one or more discrete passageways for the one or more conductors
that provide a closed path from the first end of the cable hose to
the second end of the cable hose for each of the one or more
conductors; and (3) an inner conduit configured to allow a gas to
flow from the first end to the second end.
6. The cable hose of claim 5, wherein the one or more conductors
are a plurality of conductors and the monolithic tubing is formed
around and between the EMI shield and the plurality of conductors
by molding an insulator over the plurality of conductors.
7. The cable hose of claim 2, wherein the tubing comprises: an
outer tube; and an inner tube, wherein the EMI shield is embedded
in the outer tube and the one or more conductors are disposed in an
annular compartment disposed between the outer tube and the inner
tube.
8. The cable hose of claim 1, wherein the tubing comprises: an
outer tube; and an inner tube, wherein the EMI shield is coupled to
an inner surface of the outer tube and the one or more conductors
are disposed in an annular compartment disposed between the outer
tube and the inner tube.
9. The cable hose of claim 1, wherein the EMI shield is fixed in
place within the tubing from a first end of the cable hose to a
second end of the cable hose.
10. The cable hose of claim 1, wherein the tubing defines an inner
conduit and an outer surface of the cable hose, and both the one or
more conductors and the EMI shield are disposed between the inner
conduit and the outer surface.
11. The cable hose of claim 1, wherein the cable hose connects a
power source to a plasma arc torch assembly, a first conductor of
the one or more conductors is a high frequency start conductor, and
the EMI shield is configured to prevent EMI generated by a high
frequency pulse traveling along the first conductor from exiting
the cable hose radially.
12. The cable hose of claim 11, wherein the EMI shield conducts
working current between the plasma arc torch assembly and the power
source after the high frequency pulse travels along the first
conductor.
13. The cable hose of claim 12, wherein the one or more conductors
do not transfer working current to the plasma arc torch
assembly.
14. A welding or cutting system comprising: a power source; a torch
assembly; and a cable hose extending between the power source and
the torch assembly, the cable hose including tubing, one or more
conductors, and a conductive, annular electromagnetic interference
(EMI) shield that is disposed radially interiorly of at least a
portion of the tubing and radially exteriorly of the one or more
conductors so that the EMI shield: (1) prevents EMI emanating from
the one or more conductors from exiting the cable hose; and (2)
conducts current between the power source and the torch
assembly.
15. The system of claim 14, wherein the EMI shield is embedded
within the tubing.
16. The system of claim 15, wherein the tubing of the cable hose
comprises: monolithic tubing that is disposed radially exteriorly
and radially interiorly of the EMI shield and that extends around
and between the one or more conductors to define: (1) a discrete
passageway for the EMI shield that provides a closed path from a
first end of the cable hose to a second end of the cable hose for
the EMI shield; (2) one or more discrete passageways for the one or
more conductors that provide a closed path from the first end of
the cable hose to the second end of the cable hose for each of the
one or more conductors; and (3) an inner conduit configured to
allow a gas to flow from the first end to the second end.
17. The system of claim 14, wherein the torch assembly comprises a
plasma arc torch assembly, a first conductor of the one or more
conductors is a high frequency start conductor, and the EMI shield
is configured to prevent EMI generated by a high frequency pulse
traveling along the first conductor from exiting the cable hose
radially.
18. The system of claim 17, wherein the EMI shield conducts working
current between the plasma arc torch assembly and the power source
after the high frequency pulse travels along the first
conductor.
19. A method of forming a cable hose, comprising: providing a
conductive, annular electromagnetic interference (EMI) shield for a
cable hose; arranging one or more conductors in a specific
configuration radially interiorly of the EMI shield so that the EMI
shield prevents EMI emanating from the one or more conductors from
exiting the cable hose radially; and arranging tubing radially
exterior of the EMI shield so the EMI shield can conduct current
between components of a welding or cutting system.
20. The method of claim 19, wherein the arranging comprises:
overmolding an insulator onto at least the EMI shield to secure the
EMI shield in a specific configuration from a first end of the
cable hose to a second end of the cable hose.
Description
TECHNICAL FIELD
[0001] The present disclosure is directed toward cable hoses and,
in particular, to cable hoses with an electromagnetic interference
shield that can conduct current.
BACKGROUND
[0002] Welding and cutting systems, such as plasma cutting systems,
typically include multiple interconnected components. For example,
a plasma cutting system may include a gas supply, a torch assembly,
and a clamp that are each connected to a power source that
interconnects these components. At least some of these components
are connected to the power source by cable hoses (also referred to
as leads, welding cables, etc.) that can guide welding or cutting
resources, including gas and electricity, to their intended
destination. That is, cable hoses are capable of transferring gas
and electricity. To effectuate this, cable hoses typically include
a first conduit or passageway for gas and a second conduit or
passageway for conductors.
[0003] At least some of these cable hoses include electromagnetic
interference (EMI) shields. For example, in plasma cutting torches
that utilize high frequency starting, a pulse of transient voltage
breaks down the dielectric withstand voltage of the air or medium
to create an initial arc between a cathode and anode (e.g., the
electrode and nozzle) in the torch. Although this pulse is
effective at starting an arc, the pulse may create EMI that might
damage and/or disrupt the performance of machinery/electronics in
proximity of the pulse. Consequently, cable hoses for torches with
high frequency starting often include exterior shielding to shield
against the EMI.
[0004] For example, often, outer surfaces of cable hoses are
wrapped with a grounded EMI shield so that the EMI shield can
reflect EMI or pick up the noise and conduct it to ground.
Unfortunately, external shields increase the outer diameter of a
cable hose and may deform during or due to flexure of the cable
hose (since external shields are the outermost component of a cable
hose). Additionally, it may be relatively expensive to coat the
outer tube 106 with an external shield 145 that serves no other
purpose other than shielding. Thus, often, end users may avoid
welding and cutting processes that require shielded cable hoses.
Consequently, smaller, simpler, and structurally sound cable hoses
with EMI shielding that can carry out multiple tasks are
desired.
SUMMARY
[0005] The present disclosure is directed towards cable hoses for
welding or cutting systems and methods of forming the same.
According to one embodiment, a cable hose suitable for welding or
cutting systems includes tubing, one or more conductors, and a
conductive, annular electromagnetic interference (EMI) shield. The
EMI shield is disposed radially interiorly of at least a portion of
the tubing and radially exteriorly of the one or more conductors so
that the EMI shield: (1) prevents EMI emanating from the one or
more conductors from exiting the cable hose radially; and (2)
conducts current between components of a welding or cutting system.
Advantageously, this EMI shield provides two functions and, thus,
allows components of traditional cable hoses to be eliminated from
the cable hose presented herein. Thus, the cable hose presented
herein may be smaller (and, thus, cheaper) than exterior EMI
shields. Due to its location, this EMI shield may also be more
structurally sound than external EMI shields since it may be
supported by tubing that is radially exterior of the EMI
shield.
[0006] In at least some of these embodiments, the EMI shield is
embedded within the tubing. For example, the tubing may be formed
from an insulator and the EMI shield may be embedded within the
tubing by molding the insulator over the EMI shield. Additionally
or alternatively, the one or more conductors may be embedded within
the tubing. For example, the tubing may comprise monolithic tubing
that is disposed radially exteriorly and radially interiorly of the
EMI shield and that extends around and between the one or more
conductors. In these embodiments, the monolithic tubing defines:
(1) a discrete passageway for the EMI shield that provides a closed
path from a first end of the cable hose to a second end of the
cable hose for the EMI shield; (2) one or more discrete passageways
for the one or more conductors that provide a closed path from the
first end of the cable hose to the second end of the cable hose for
each of the one or more conductors; and (3) an inner conduit
configured to allow a gas to flow from the first end to the second
end. Moreover, in some of these embodiments, the one or more
conductors are a plurality of conductors and the monolithic tubing
is formed around and between the EMI shield and the plurality of
conductors by molding the insulator over the plurality of
conductors. Embedding the EMI shield and/or the conductors in the
tubing may offer a number of advantages, including added structural
integrity.
[0007] In other embodiments where the EMI shield is embedded within
the tubing, the tubing includes an outer tube and an inner tube. In
these embodiments, the EMI shield is embedded in the outer tube and
the one or more conductors are disposed in an annular compartment
disposed between the outer tube and the inner tube. Alternatively,
the EMI shield need not be embedded in the tubing. For example, in
some of embodiments, the tubing includes an outer tube and an inner
tube, the EMI shield is coupled to an inner surface of the outer
tube, and the one or more conductors are disposed in an annular
compartment disposed between the outer tube and the inner tube.
Thus, the internal EMI shield can be easily added to any number of
cable hoses, even cable hoses manufactured with preset
manufacturing processes.
[0008] Moreover, in some embodiments of the cable hose provided
herein, the EMI shield is fixed in place within the tubing from a
first end of the cable hose to a second end of the cable hose.
Additionally or alternatively, the tubing may define an inner
conduit and an outer surface of the cable hose, and both the one or
more conductors and the EMI shield may be disposed between the
inner conduit and the outer surface.
[0009] Still further, in some embodiments, the cable hose connects
a power source to a plasma arc torch assembly, a first conductor of
the one or more conductors is a high frequency start conductor, and
the EMI shield is configured to prevent EMI generated by a high
frequency pulse traveling along the first conductor from exiting
the cable hose radially. This may allow high frequency starting
plasma arc torches to be used in close proximity with electronics,
such as electronics for automated operations (e.g., computer
numerical control (CNC) machines) and, thus, may allow end users to
leverage advantages of high frequency starting torches for various
operations that often cannot use high frequency starting torches,
such as automated cutting operations. In at least some of these
embodiments, the EMI shield conducts working current between the
plasma arc torch assembly and the power source after the high
frequency pulse travels along the first conductor. In at least some
of these embodiments, the one or more conductors do not transfer
working current between the plasma arc torch assembly and the power
source. Thus, the cable hose presented herein may include less
conductors than other cable hoses and the cable hose presented
herein may be lighter, smaller, and/or cheaper than other cable
hoses.
[0010] According to another embodiment, a welding or cutting system
is presented herein. The system includes a power source, a torch
assembly, and a cable hose that extends between the power source
and the torch assembly. The cable hose includes tubing, one or more
conductors, and a conductive, annular electromagnetic interference
(EMI) shield that is disposed radially interiorly of at least a
portion of the tubing and radially exteriorly of the one or more
conductors. Thus, the EMI shield: (1) prevents EMI emanating from
the one or more conductors from exiting the cable hose; and (2)
conducts current between the power source and the torch
assembly.
[0011] According to yet another embodiment, a method of forming a
cable hose is presented herein. The method includes providing a
conductive, annular electromagnetic interference (EMI) shield for a
cable hose and arranging one or more conductors in a specific
configuration radially interiorly of the EMI shield so that the EMI
shield prevents EMI emanating from the one or more conductors from
exiting the cable hose radially. The method also includes arranging
tubing radially exterior of the of the EMI shield so the EMI shield
can conduct current between components of a welding or cutting
system.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0012] FIG. 1 is a perspective view of a cutting system including a
gas supply, a power source, a torch assembly, and at least one
cable hose with a conductive electromagnetic interference shield
formed in accordance with an example embodiment of the present
disclosure.
[0013] FIG. 2 is a perspective sectional view of an embodiment of a
cable hose with a conductive electromagnetic interference shield
formed in accordance with an example embodiment of the present
disclosure.
[0014] FIGS. 3A and 3B are front sectional views of two additional
embodiments of a cable hose with a conductive electromagnetic
interference shield formed in accordance with example embodiments
of the present disclosure.
[0015] FIGS. 4A and 4B are high-level circuitry diagrams depicting
electrical connections provided by a cable hose with a conductive
electromagnetic interference shield formed in accordance with
example embodiments of the present disclosure.
[0016] FIG. 5 is a high-level flow chart illustrating a method for
forming a cable hose with a conductive electromagnetic interference
shield in accordance with an example embodiment of the present
disclosure.
[0017] Like numerals identify like components throughout the
figures.
DETAILED DESCRIPTION
[0018] An improved cable hose and method for forming the same are
presented herein. The cable hose includes a conductive
electromagnetic interference (EMI) shield that surrounds (e.g.,
circumferentially encloses) one or more conductors disposed in the
cable hose to provide shielding for any EMI emanating from the one
or more conductors. Additionally, and importantly, the internal EMI
shield conducts operational current for cutting or welding
operations. For example, if the cable hose presented herein
connects a power source to a plasma torch assembly utilizing a high
frequency start, the internal EMI shield may provide shielding for
a high frequency pulse and, after the pulse has passed, the
internal EMI shield may conduct working current between the plasma
torch assembly and the power source. Since the EMI shield conducts
current, the cable hose can include less conductors as compared to
shielded cable hoses that require one or more conductors dedicated
to conducting working current. For at least this reason, the cable
hose presented herein may have a reduced size, weight, and/or cost
of manufacturing as compared to other shielded cable hoses.
Moreover, since the EMI shield conducts current while a media
(e.g., gas or liquid) flows through the cable, the media may cool
the EMI shield (e.g., transfer resistive heat away from the EMI
shield) during current conduction and, thus, the EMI shield can be
formed with relatively light gauge wires to further reduce the
size, weight, and/or cost of the cable hose.
[0019] The conductive EMI shield presented herein is also
"internal," insofar as "internal" means that the EMI shield is
disposed radially interiorly of at least a portion of insulating
tubing used to form the cable hose. For example, in some
embodiments, an EMI shield may be coupled to and/or positioned
adjacent to the inner surface 107 of the outer tube 106.
Alternatively, the internal EMI shield presented herein may be
embedded in tubing of a cable hose. For example, at least a portion
of the cable hose may be formed from unitary or monolithic (i.e.,
one-piece) tubing and the EMI shield may be embedded in the
monolithic tubing (e.g., the tubing may be overmolded on the EMI
shield and/or conductors). Notably, since the EMI shield serves as
an electrical conductor, the EMI shield should not be the outermost
component of a cable hose. If the EMI shield were the outermost
component, the cable hose might shock or injure an end user who
bumps, grabs, or otherwise contacts the cable hose while it is
conducting current thought the EMI shield. In fact, unless the EMI
shield is insulated from an outer surface of a cable hose and other
conductive components included in the cable hose, an EMI shield
cannot be conductive. For example, an EMI shield resting on an
uninsulated conductor should not be conductive.
[0020] Regardless of how the EMI shield is positioned within a
cable hose, an internal EMI shield may have a reduced overall size
as compared to an external EMI shield, which may reduce the cost of
manufacturing/procuring the EMI shield. For example, the EMI shield
may have a reduced diameter as compared to exterior shielding that
is applied to the outer dimensions of a cable hose as a coating and
thus, may be manufactured from less material (at less cost).
Additionally, when a cable hose includes an exterior EMI shield,
the EMI shield may deform or develop holes during and/or due to
flexure of the cable hose. By comparison, when the EMI shield is
disposed within at least a portion of tubing, the tubing may
maintain the form factor, spacing, and integrity of the EMI shield
and prevent or discourage deformation of the EMI shield, especially
if the EMI shield is embedded within tubing. That is, the tubing
may prevent, or at least discourage, holes from forming in an
internal EMI shield during and/or due to flexure of the cable hose.
An internal, annular EMI shield may also have a large surface area
that is equidistant from a gas flow passage (e.g., an internal
surface of the EMI shield may have a constant or uniform proximity
to a media (e.g., gas or liquid) flowing through the cable hose)
and thus, the EMI shield may experience enhanced cooling at least
as compared to a single wire mounted in a particular location
within the insulation of a cable hose (which only has a small
surface area disposed proximate flowing media).
[0021] FIG. 1 illustrates an example embodiment of cutting system
150 that may utilize the cable hose presented herein. At a
high-level, the depicted cutting system 150 includes a power source
160 that supplies power to a torch assembly 170. The power source
160 also controls the flow of gas from a gas supply 180 to the
torch assembly 170 (however, in other embodiments, the power source
160 might supply the gas itself). The gas supply 180 is connected
to the power source via cable hose 182 and the power source 160 is
connected to the torch assembly 170 via cable hose 172. The cutting
system 150 also includes a working lead 192 with a grounding clamp
190. As is illustrated, cable hose 172, cable hose 182, and/or
cable hose 192 may each be any length. In order to connect the
aforementioned components, the opposing ends of cable hose 172,
cable hose 182, and/or cable hose 192 may each be coupled to the
power source 160, torch assembly 170, gas supply 180, or clamp 190
in any manner now known or developed hereafter (e.g., a releasable
connection).
[0022] Although not shown, the cable hoses presented herein might
also be used in welding systems, automated cutting systems, and/or
any other system in which welding/cutting resources or signals
might need to flow between two components. In fact, since the cable
hoses presented herein shield EMI, the cable hoses presented herein
may allow plasma arc torches utilizing a high frequency start
method to be used with automated equipment, such as computer
numerical control (CNC) machines/controllers, with reduced or no
EMI shielding (e.g., the automated equipment may have reduced
shielding as compared to equipment typically used with high
frequency starting plasma arc torches). That is, the cable hose
presented herein may allow torches with high frequency starting to
be used with automated equipment because the cable hose may
effectively and efficiently shield the EMI generated by a high
frequency start to negate risks associated with EMI emission. This
may provide a significant savings for automated setup and may also
be advantageous because in at least some instances, high frequency
starting may be advantageous as compared to other starting methods.
For example, high frequency starting may minimize the time that a
pilot arc is maintained in the torch assembly, which may extend the
life of various consumable components included in a plasma arc
torch. Consequently, the cable hoses presented herein may improve
the quality and/or lifespan of torches that can be used with
automated cutting (or welding operations).
[0023] The cable hose presented herein may be most useful as cable
hose 172 (e.g., to transfer signals, current, gas, etc. between a
power source and a torch assembly while also shielding EMI
generated by the current and/or signals, and, in particular, EMI
generated by a high frequency pulse); however, the cable hose
presented herein may also be used as cable hose 182 (e.g., to
transfer signals and gas between a power source and a gas supply
while shielding EMI generated by any signals), and/or cable hose
192 (e.g., to transfer signals and current between a power source
and a clamp while shielding EMI generated by the signals and/or
current) if desired. Additionally, as mentioned above, the cable
hose presented herein can be used for any welding or cutting
operations in which welding/cutting resources or signals might need
to flow between two components with EMI shielding.
[0024] Now turning to FIGS. 2, 3A, and 3B, but with an emphasis on
FIG. 2, generally, the cable hose presented herein extends from a
first end 202 (e.g., an end that can connect to a power source) to
a second end 204 (e.g., an end that can connect to a torch
assembly). More specifically, the cable hose presented herein
includes tubing 210 and an inner conduit 210. The tubing 210
provides a path from the first end 202 to the second end 204 for a
specific configuration of an annular, conductive EMI shield 250 and
one or more conductors 240. Meanwhile, the inner conduit 220 is
configured to allow a welding resource, such as gas or a welding
wire, to flow/travel from the first end 202 of the cable hose to
the second end 204 of the cable hose. The length "L" between the
first end 202 and the second end 204 can be any desirable length,
such as a length in the range of approximately three (3) feet to
approximately one hundred fifty (150) feet. Although this length is
only shown in FIG. 2, it is to be understood that the cable hose
300 shown in FIG. 3A and the cable hose 301 shown in FIG. 3B may
also have any desirable length.
[0025] Still referring to FIGS. 2, 3A, 3B, each of the depicted
embodiments includes one or more conductors 240 that are disposed
radially interiorly of an annular, internal, conductive EMI shield
250. The EMI shield 250 is an annular shield formed from braided
(i.e., interweaved) conductors, such as aluminum, copper-clad
aluminum, or copper electrical conductors. In most embodiments, the
EMI shield is formed by braiding the conductors into an annular
shape; however, in some embodiments, conductors might be braided
into a flat member that is subsequently formed into an annular
shape (and shields formed in either manner may be referred to
herein as "annular"). The braid may have any desirable thickness,
ranging from the thickness of one wire to the thickness of ten
wires. However, notably, a one wire-thick braid may be sufficient
to prevent EMI from escaping the cable hose and to conduct
operational current between components of a welding or cutting
system.
[0026] In fact, as mentioned above, in at least some embodiments,
the EMI shield 250 may be formed from light gauge wires because the
resistive heat (e.g., I.sup.2R losses, with I representing current
and R representing resistance) generated by the EMI shield 250 when
the EMI shield 250 is conducting current (in the manner explained
in detail below) can be carried away by a media (e.g., gas or
liquid) flowing through the inner conduit 220 of the cable hose
200. This cooling (e.g., removal of resistive heat) may be
facilitated/ensured by at least two aspects of the present cable
hose. First, since the EMI shield 250 is an annular, internal EMI
shield 250, an inner or internal surface EMI shield 250 may have
consistent proximity to the inner conduit 220 and may enhance
cooling of the EMI shield 250, at least as compared to the cooling
provided by the conduit 220 to a single wire mounted within the
tubing 210 of the cable hose 200 (e.g., one of the conductors 240).
Second, since the EMI shield 250 only conducts working current
(e.g., direct current (DC)) while gas is flowing through the inner
conduit 220 (as is also explained in further detail below), the EMI
shield 250 will be continually cooled while functioning to conduct
current (thereby enabling the use of an EMI shield 250 formed from
relatively low gauge wire).
[0027] As mentioned above, the EMI shield 250 is an "internal" EMI
shield because the EMI shield 250 is disposed within at least a
portion of tubing 210 used to form the cable hose. However, in
different embodiments, the EMI shield 250 may be disposed within
different portions of the tubing 210. For example, in the example
embodiment depicted in FIG. 2, the EMI shield 250 and the
conductors 240 are embedded within monolithic tubing 210. By
comparison, in the example embodiment depicted in FIG. 3A, the EMI
shield 250 is embedded within an outer tube 306 of tubing 210 while
the conductors 240 are disposed in a compartment formed between the
outer tube 306 and an inner tube 302. Still further, in the example
embodiment depicted in FIG. 3B, the EMI shield 250 is disposed on
or adjacent an inner surface 307 of an outer tube 306 of tubing 210
while the conductors 240 are disposed in a compartment formed
between the outer tube 306 and an inner tube 302. Each of these
embodiments is addressed in more detail below.
[0028] The conductors included in the embodiments depicted in FIGS.
3, 4A, and 4B, which are generally referred to as conductors 240,
may include electrical conductors that can pass current and signals
and/or optical conductors that can pass optical images and/or
signals. For example, the conductors 240 may be aluminum,
copper-clad aluminum, or copper electrical conductors and/or fiber
optic optical conductors. In various embodiments, the conductors
240 may include various conductors dedicated to specific tasks.
Additionally, if desired, the conductors 240 may include
individualized insulation 241 (see FIGS. 3A and 3B); however,
individualized insulation 241 may not be necessary if the
conductors 240 are embedded within a portion of the tubing 210, as
is discussed at length in U.S. patent application Ser. No.
16/110,180, filed on Aug. 23, 2018, and entitled "Cable Hose with
Embedded Features," which is hereby incorporated by reference in
its entirety.
[0029] By way of example, in FIG. 2, the conductors 240 are each
labeled. The conductors 240 include a first conductor 242 for
conducting high frequency pulses, a second conductor 244 for
conducting operational signals, and a third conductor 246 and
fourth conductor 248 for conducting consumable identification
signals. None of conductor 242, conductor 244, conductor 246, and
conductor 248 in FIG. 2 include individualized insulation.
Moreover, notably, since the EMI shield 250 can conduct
operational/working current, none of the conductors 240 (e.g., none
of conductor 242, conductor 244, conductor 246, and conductor 248)
need to be dedicated to conducting operational/working current.
Instead, conductors for working current can be omitted or removed
from the cable hose (so that the cable hose includes less
conductors 240 than a similar cable hose with a non-conductive or
grounded EMI shield). Nonetheless, the conductors shown in FIG. 2
are merely example conducts and in other embodiments, any desirable
conductors 240 aside from working current conductors may be
disposed radially interiorly of the EMI shield 250. For example,
the unlabeled conductors 240 in FIGS. 3A and 3B may be any
desirable conductors aside from working current conductors.
[0030] Still referring to FIGS. 2, 3A, and 3B, the tubing 210
included in the cable hose presented herein is an electrical
insulator, such as chlorinated polyethylene (PE), neoprene,
polyvinyl chloride, silicone, polyolefin, ethylene propylene diene
monomer (EPDM), acrylonitrile butadiene styrene (ABS) blends, or a
combination thereof that is suitable of preventing current from
leaking radially from the cable hose and/or for discouraging
electrical or optical signals from exiting the cable hose 200
radially (although the tubing 210 may be ineffective at shielding
EMI). The material forming the tubing 210 can also withstand the
pressure of one or more working gases or fluids (or objects, such
as welding wire) passing through an inner conduit 220 formed within
the cable hose 200 and, thus, can protect (e.g., insulate) the EMI
shield 250 and any electrical and or optical conductors 240
disposed within (e.g., embedded in) the tubing 210.
[0031] Now turning specifically to FIG. 2, as mentioned, in at
least some embodiments, the cable hose 200 is formed from unitary
or monolithic tubing 210. In FIG. 2, the tubing 210 is annular,
monolithic tubing that extends from an inner surface or wall 212 to
an outer surface or wall 216. The inner wall 212 defines an inner
conduit 220 that may be suitable to guide gas (e.g., shielding gas,
process gas, etc.), fluid (e.g., coolant, water, etc.), and/or wire
(e.g., welding wire) from the first end 202 to the second end 204.
In the depicted embodiments, the inner wall 212 and outer wall 216
have concentric and symmetrical or regular geometries; however, in
other embodiments, the inner wall 212 and/or outer wall 216 need
not be symmetrical and, instead, may be irregular, eccentric,
and/or have any desirable configuration. For example, the outer
wall 216 might be elliptical and the inner wall 212 might be a
circular wall disposed adjacent one end of the elliptical outer
wall 216.
[0032] A thickness "T" of the tubing 210 is defined by the
difference between an outer diameter "OD" and an inner diameter
"ID" and, in various embodiments, the thickness "T" may be adjusted
by changing the inner diameter ID, the outer diameter OD, or both,
to customize the cable hose 200 for any specifications. For
example, in some instances, it may be desirable to expand the
thickness T so that the tubing 210 can accommodate more conductors
240 and/or provide more insulation between conductors 240, as is
discussed at length in U.S. patent application Ser. No. 16/110,180,
filed on Aug. 23, 2018, and entitled "Cable Hose with Embedded
Features," which is hereby incorporated by reference in its
entirety.
[0033] In at least some embodiments, the tubing 210 is formed by
overmolding a material, such as an electrical insulator, over one
or more conductors 240 and the EMI shield 250. Consequently, the
tubing 210 extends radially interiorly and radially exteriorly of
the EMI shield 250 and also extends around and between the
conductors 240. This secures each of the conductors 240 and the EMI
shield 250 in a discrete position over the length L of the cable
hose 200. That is, the tubing 210 creates a closed path from the
first end 202 of the cable hose 200 to the second end 204 of the
cable hose 200 for each conductor 240 and the EMI shield 250 so
that the conductors 240 and the EMI shield 250 are not accessible
from a location that is radially exterior of the cable hose 200.
Instead, the conductors 240 and the EMI shield 250 are accessible
from only the first end 202 or the second end 204. This prevents
signals, current, and EMI from exiting the cable hose 200 radially
and, instead, suppresses EMI while causing signals and current (in
addition to gas, fluid, etc. traveling in the inner conduit 220),
to traverse the cable hose 200 end-to-end (e.g., from the first end
202 to the second end 204). Moreover, since the tubing 210 defines
discrete passageways that secure each of conductors 240 and the EMI
shield 250 in a particular location or configuration along the
length L of the cable hose 200 (from the first end 202 to the
second end 204), the EMI shield 250 may be protected from
deformation caused by flexure of the cable hose 200.
[0034] Now turning to FIGS. 3A and 3B, in these embodiments, cable
hoses 300 and 301 are each formed from multiple pieces of tubing
210, but the EMI shield 250 is still internal to at least a portion
of tubing 210. More specifically, in the embodiments depicted in
FIGS. 3A and 3B, the tubing 210 includes an inner tube 302 with an
inner surface 303 and an outer surface 304 and an outer tube 306
with an inner surface 307 and an outer surface 308. The inner
surface 303 of the inner tube 302 defines an inner conduit 320 and
the outer surface 304 of the inner tube 302 cooperates with the
inner surface 307 of the outer tube 306 to define an annular
compartment 310.
[0035] In cable hose 300 (FIG. 3A), the EMI shield 250 is embedded
within the outer tube 308. Thus, in cable hose 300, the conductive
EMI shield may be insulated from the conductors 240 by tubing 210.
By comparison, in cable hose 301 (FIG. 3B), the EMI shield 250 is
disposed on the inner surface 307 of the outer tube 306 and is
insulated from the conductors 240 by filler material 330 and/or
individualized insulation 241 included on the conductors 240. In at
least some of embodiments, the EMI shield 250 is coupled to (e.g.,
affixed to) the inner surface 307 of the outer tube 306 in order to
ensure it remains isolated from the conductors 240 (and to protect
the EMI shield 250 from flexure). Alternatively, the filler
material 330 may be an annular filler material 330 that is disposed
in the annular compartment 310 and ensures that the EMI shield
remains electrically isolated from the conductors 240. Regardless,
in both of the embodiments depicted in FIGS. 3A and 3B, the EMI
shield 250 surrounds the annular compartment 310 and, thus, any EMI
emanating from conductors 240 will be shielded by the EMI shield
250.
[0036] Now turning to FIGS. 4A and 4B, these Figures illustrate, at
a high-level, the electrical circuitry provided by a cable hose
including a conductive, internal EMI shield. That is, FIGS. 4A and
4B illustrate how the internal EMI shield 250 may shield EMI
emanating from conductors 240 and may also conduct working current
from one end (e.g., end 202) of the cable hose to an opposite end
of the cable hose (e.g., end 204), in either direction. Since this
functionality may be particularly useful for plasma arc torches
utilizing a high frequency start, this functionality is described
below with respect to a high-frequency pulse traveling along a
conductor 242 (see FIG. 2) that is dedicated to high frequency
starting. However, the example shown in FIGS. 4A and 4B is merely
an example and the internal EMI shield presented herein may shield
EMI generated by any current or conductor and may conduct current
for any task. That is, if the cable hose presented herein is used
for operations other than connecting a power source to a plasma arc
torches utilizing a high frequency start, the EMI shield 250 will
still not run to ground and, thus, may still conduct current
between two components of a cutting or welding system.
[0037] That all being said, when the cable hose presented herein is
connecting a power source 402 and high frequency starting plasma
arc torch assembly 404, the EMI shield 250, together with other
conductors/cable hoses, completes a circuit between either the
power source 402 and the plasma arc torch assembly 404 (see FIG.
4A) or the power source 402, the plasma torch assembly 404, and a
workpiece 430 (see FIG. 4B). That is, during arc initiation, the
EMI shield 250 and conductor 242 complete a circuit between the
power source 402 and the plasma arc torch assembly 404 as is shown
in FIG. 4A (a pilot arc connects an anode 405 and a cathode 406
disposed in the torch assembly 404 to complete this circuit,
despite not being shown in FIG. 4A). Then, during operations of the
torch assembly 404 (e.g., cutting operations), the working lead 192
and grounding clamp 190, the EMI shield 250, and a plasma arc "PA"
complete a circuit between the power source 402, the torch assembly
404, and the workpiece 430.
[0038] More specifically, in FIG. 4A, the power source 402 is shown
delivering a pulse of high frequency current (illustrated at 410
and also referred to herein as "high frequency pulse" or "pulse")
to an anode 405 disposed in the torch assembly 404 along conductor
242 during arc initiation for a plasma torch assembly 404. The
conductor 242 connects the power source 402 to the anode 405 and
the pulse causes initiation of a pilot arc between the anode 405
(e.g., a torch tip) and the cathode 406 (e.g., an electrode).
Meanwhile the EMI shield 250 connects the power source 402 to the
cathode 406 and, thus, the EMI shield 250 closes a circuit between
the power source 402 and the torch assembly 404. Consequently,
during arc initiation, current may travel from the power source 402
to the torch assembly 404 along conductor 242 (as depicted at 410)
and current may travel from the torch assembly 404 to the power
source 402 along the EMI shield 250 (as depicted at 412), insofar
as current movement is being described herein in accordance with
conventional current terminology, as opposed to electron flow
terminology.
[0039] Since the conductor 242 and EMI shield 250 are each
conducting current during starting (i.e., during arc initiation),
as is shown at 410 and 412 in FIG. 4A, the electrical fields
generated by a pulse of high frequency current (e.g., as
illustrated at 410) will cancel out. In fact, despite the different
sizes of arrows 410 and 412, the conductor 242 and EMI shield 250
may, in at least some embodiments, conduct equal current during
starting so that the electrical fields are canceled or zeroed out
and EMI generated by the high frequency pulse (illustrated at 414)
is prevented from exiting the cable hose. Since the conductor 242
may not be perfectly centered within the EMI shield 250, the
electrical fields may not be perfectly canceled out; however, the
achieved cancellation may be sufficient to prevent harmful EMI from
escaping the cable hose.
[0040] Once the pulse 410 generates an arc between the anode 405
and the cathode 406, the torch assembly 404 is moved towards a
workpiece 430 until the arc jumps to the workpiece to establish a
plasma arc "PA," as shown in FIG. 4B. As the plasma arc PA is
established, the power source 402 may cut off power to the anode
405 while sending working current 422 to the torch assembly 404 via
the workpiece 430 (again, in accordance with conventional current
terminology). For example, although not shown, the power source 402
might include a DC power supply arranged in parallel with a
combination of at least a high frequency generator, one or more
resistors, and pilot arc contacts. In this scenario, the pilot arc
contacts may open as the plasma arc PA is established so that the
power source delivers DC current to the cathode 406 and workpiece
430 without delivering current to the anode 405.
[0041] Regardless of how the power source 402 switches from arc
initiation to an operational mode, during operation of the torch
assembly 404, the EMI shield 250 forms a portion of a closed
circuit that allows working current 422 to flow between the power
source 402, the torch assembly 404, and the workpiece 430. In
particular, the working current 422 flows from a positive terminal
of the power source 402, through the working lead 192 and grounding
clamp 190, to the workpiece 430 (again, insofar as this description
conforms with conventional current terminology). The working
current 422 then flows from the workpiece 430 to the cathode 406 of
the torch assembly via the plasma arc PA and, finally, flows from
the cathode 406 back to the power source 402 (e.g., to a negative
terminal of a DC power source 402) via the EMI shield 250. Thus,
the EMI shield 250 allows working current to flow between the torch
assembly 404 and the power source 402. Moreover, although
conventional current terminology is used herein, it is to be
understood that this terminology indicates that electrons are
flowing from the power source 402 to the cathode 406 via the EMI
shield 250 during operation of the torch assembly 404. Thus, in
some instances, the EMI shield 250 may be described as being
configured to deliver power to a torch assembly 404.
[0042] FIG. 5 depicts a high-level flow chart illustrating a method
500 for forming a cable hose with an internal, conductive EMI
shield in accordance with an example embodiment of the present
disclosure. At 502, a conductive EMI shield is provided (e.g.,
procured or formed/manufactured by braiding conductive wires into
an annular braid). At 504, one or more of conductors are arranged
in a specific configuration radially interiorly of the EMI Shield.
For example, a set of uninsulated or insulated conductors can be
aligned in a straight or helical configuration around a
circumference of a cross-sectional area. Arranging the conductors
radially interiorly of the EMI shield prevents, or at least
discourages, EMI emanating from the one or more conductors from
exiting the cable hose radially.
[0043] At 506, tubing (e.g., an insulator) is arranged radially
exteriorly of the EMI shield. For example, in at least some
embodiments, tubing is overmolded onto the one or more conductors
and the EMI shield to form a monolithic tubing that extends around
and between the EMI shield and the one or more conductors to secure
the EMI shield and the one or more conductors in the specific
configuration and to define an inner conduit, as is shown in FIG.
2. Alternatively, tubing may be overmolded onto only the EMI shield
and the one or more conductors may be confined between an inner
tube and an outer tube, as is shown in FIG. 3A. Still further, the
tubing may simply be formed around (e.g., radially exteriorly of)
the EMI shield and the EMI shield and the one or more conductors
may be confined between an inner tube and an outer tube, as is
shown in FIG. 3B. Regardless of how the tubing (e.g., tubing 210)
is arranged radially exteriorly of the EMI shield, providing tubing
in this position covers the EMI shield with an insulator and, thus,
renders it safe for the EMI shield to conduct current between
components of a welding or cutting system.
[0044] To summarize, in one form a cable hose suitable for welding
or cutting systems is presented herein, the cable hose comprising:
tubing; one or more conductors; and a conductive, annular
electromagnetic interference (EMI) shield that is disposed radially
interiorly of at least a portion of the tubing and radially
exteriorly of the one or more conductors so that the EMI shield:
(1) prevents EMI emanating from the one or more conductors from
exiting the cable hose radially; and (2) conducts current between
components of a welding or cutting system.
[0045] In another form, a welding or cutting system is presented
herein, the system comprising: a power source; a torch assembly;
and a cable hose extending between the power source and the torch
assembly, the cable hose including tubing, one or more conductors,
and a conductive, annular electromagnetic interference (EMI) shield
that is disposed radially interiorly of at least a portion of the
tubing and radially exteriorly of the one or more conductors so
that the EMI shield: (1) prevents EMI emanating from the one or
more conductors from exiting the cable hose; and (2) conducts
between the power source and the torch assembly.
[0046] In yet another form, method of forming a cable hose is
presented herein, the method comprising: providing a conductive,
annular electromagnetic interference (EMI) shield for a cable hose;
arranging one or more conductors in a specific configuration
radially interiorly of the EMI shield so that the EMI shield
prevents EMI emanating from the one or more conductors from exiting
the cable hose radially; and arranging tubing radially exterior of
the EMI shield so the EMI shield can conduct current between
components of a welding or cutting system.
[0047] Although the techniques are illustrated and described herein
as embodied in one or more specific examples, the specific details
of the examples are not intended to limit the scope of the
techniques presented herein, since various modifications and
structural changes may be made within the scope and range of the
invention. For example, a cable hose formed in accordance with the
techniques presented herein may include any number of embedded
conductors, arranged in any desirable configuration within the EMI
shield. In addition, various features from one of the examples
discussed herein may be incorporated into any other examples.
Accordingly, the appended claims should be construed broadly and in
a manner consistent with the scope of the disclosure.
* * * * *